A mother board and a daughter board are electrically interconnected to transfer digital signals between respective assemblies used in a computer or other electronic equipment, by way of example. The mother and daughter boards may be arranged perpendicular to each other, as in an "edge card" configuration, depending upon the design of the overall product.
In a variety of other product applications, the prior art has used compressible electrical connectors which are well known in the electronic industry. These compressible electrical connectors include a plurality of closely spaced conductive elements or traces photographically etched or otherwise formed on a flexible film which is bonded to an elastomeric core or other suitable carrier. Under its trademark "AMPLIFLEX", AMP Incorporated of Harrisburg, Pennsylvania, supplies a wide variety of such compressible electrical connectors to the electronic and aerospace industries.
Because of their relatively high circuit densities, it would be desirable to use these "AMPLIFLEX" compressible electrical connectors in certain product applications having mother/daughter board configurations. However, because the daughter board is slidably inserted into the mother board, perpendicularly thereof, the compressible electrical connector may become damaged inadvertently.
It is important, therefore, to have a very low or substantially zero insertion force (ZIF) to preclude damage to the compressible electrical connector. This is required for insertion of the boards during assembly of the equipment in production as well as withdrawal of the boards during maintenance and service of the equipment in the field.
In co-pending U.S. patent application Ser. No. 07/938,989, owned by the Assignee hereof, a ZIF type interconnection system is taught utilizing flexible film circuitry. The electrical assembly thereof includes a mother board, a connector body mounted on the mother board, and at least one compressible electrical connector carried by the connector body. A daughter board is arranged to be slidably inserted within the connector body and is disposed substantially perpendicularly to the mother board. The daughter board has respective sides and further has respective circuit elements electrically connected to the compressible electrical connector on the connector body. A deflection means is carried by the connector body and engages one of the sides of the daughter board to deflect the daughter board away from the compressible electrical connector as the daughter board is slidably inserted into the connector body. Further, a retaining means is provided to exert a lateral clamping force on the daughter bard and against the connector body, after the daughter board has been inserted into the connector body, thereby removably retaining the daughter board on the mother board.
Co-pending U.S. patent application Ser.No. 07/995,474, assigned to the assignee hereof, teaches another approach to a ZIF connector assembly for mother/daughter boards. More precisely, such co-pending application discloses a backplane connector having a mother board provided with a connector housing for receiving a daughter board perpendicularly thereof. A cam bump is provided on the daughter board to engage an inclined camming surface on the connector housing on the mother board, thereby deflecting the daughter board laterally away from a flexible electrical connector in the connector housing on the mother board. When the daughter board is fully seated within the connector housing on the mother board, the cam bump is received in a cam bump recess on the connector housing. A spring is provided on the connector housing to bias the daughter board towards the mother board thereby providing a detent action therebetween.
The present invention offers a still different approach in providing an electrical interconnection between a mother/daughter board utilizing flexible film having circuitry thereon as the interconnection means. This approach will become apparent in the description which follows, particularly when read in conjunction with the accompanying drawings.